Actually, you can put in a RAID array and use your old HD as a secondary. I read an article about it in a Computer Shopper a while back. I think it was June 2004 issue.
Matbe you can get the back issue... or I might send you a copy of the article... Let me know when you get your other Seagate.
They used Data Lifegaurd Tools (that came with a Raptor drive) to migrate everything from the old drive to the RAIDed ones.